My topic is extraterrestrial intelligence. Following current conventions, I use the abbreviation ‘ETI’ to stand for three related concepts: the abstract idea of extraterrestrial intelligence, individuals who are both extraterrestrial and intelligent, and the hypothesis that there are ETIs. SETI is the search for ETIs, and CETI is the attempt to communicate with ETIs. In this paper, I will try to answer the two most basic questions in extraterrestrial studies. First, what is the status of the ETI hypothesis? In (...) the light of what we know, how likely is it that there are ETIs? Secondly, what is the value of pursuing SETI? Are the expected epistemic and pragmatic payoffs sufficient to warrant an extensive search? The first, substantive question is discussed in Section 2, Section 3 and Section 4. The second, ‘program evaluation’ question is the subject of Section 5 and Section 6. But first we'll take a brief look at some of the early history of the topic. (shrink)

Mathematics is as much a part of our humanity as music and art. And it is our mathematics that might be understandable, even familiar, to a distant race and might provide the basis for mutual communication. This book discusses, in a conversational way, the role of mathematics in the search for extraterrestrial intelligence. The author explores the science behind that search, its history, and the many questions associated with it, including those regarding the nature of language and the philosophical/psychological motivation (...) behind this search. (shrink)

The well-known argument against the Search for ExtraTerrestrial Intelligence (SETI) due to George Gaylord Simpson is re-analyzed almost half a century later, in the light of our improved understanding of preconditions for the emergence of life and intelligence brought about by the ongoing “astrobiological revolution”. Simpson’s argument has been enormously influential, in particular in biological circles, and it arguably fueled the most serious opposition to SETI programmes and their funding. I argue that both proponents and opponents of Simpson’s (...) argument have occasionally mispresented its core content. Proponents often oversimplify it as just another consequence of biological contingency, thus leaving their position open to general arguments limiting the scope of contingency in evolution (such as the recent argument of Geerat Vermeij based on selection effects in the fossil record). They also tend to neglect that the argument has been presented as essentially atemporal, while referring to entities and processes that are likely to change over time; this has become even less justifiable as our astrobiological knowledge increased in recent years. Opponents have failed to see that the weaknesses in Simpson’s position could be removed by restructuring of the argument; I suggest one way of such restructuring, envisioned long ago in the fictional context by Stanislaw Lem. While no firm consensus has emerged on the validity of Simpson’s argument so far, I suggest that, contrary to the original motivation, today it is less an anti-SETI argument, and more an astrobiological research programme. In this research programme, SETI could be generalized into a platform for testing some of the deepest assumptions about evolutionary continuity and the relative role of contingency versus convergence on unprecedented spatial and temporal scales. (shrink)

In October 2014, a European Commission conference discussed SETI (Science, Engineering, Technology and Industry) achievements and their potential future impact on the economy and individuals’ well-being. This article highlights and discusses three of the salient features to emerge from the conference: the connection between science and technology, the issue of data privacy, and the need to develop ethical foresight.

This article compares justifications of the search for extraterrestrial intelligence (SETI) presented by scientists with ideational constructs associated with cargo cults in Melanesia. In focusing on similarities between cargoism and SETI, I argue that, understood in terms of cultural practice, aspects of the science of SETI have significant similarities to the religious elements that characterize cargoism. Through a focus on the construction of meanings, I consider how SETI and cargoism use similar signification systems to communicate meaning (...) related to local social contexts and I draw a parallel with the religious and meaning structure of cargoism to show that SETI and cargoism employ similar strategies to justify beliefs. As a result, in some ways SETI represents a scientific framework that inhabits cultural and epistemological space that overlaps with religious space. (shrink)

SETI scientists have done this by looking for the equivalent of television signals that might emanate from the planet of a civilization that uses radio-wave broadcasts as we do. They have found no evidence of the equivalent of our radio/TV signals in our galactic neighborhood, but that result is inconclusive. Galactic civilizations may be so different or so far ahead of us that they don't use radio waves to communicate. Or perhaps it's just that TV-watching is incompatible with advanced (...) intelligence. (shrink)

Developments that suggest the universe is full of life make the Fermi paradox increasingly pressing, but our search for an extraterrestrial technological civilization (“ETC”) is handicapped by our ignorance of its probable nature and behavior. This paper offers a way around this problem by drawing on information theoretical concepts, including game theory and Bayesian probability. It argues that, whatever its ultimate goals, an ETC would have the same instrumental goals as other intelligent agents. Generically, these are self-preservation and the acquisition (...) of resources. For an advanced ETC, these generic goals imply the objectives of removing existential threats and acquiring strategic and non-strategic information. Since the most problematic existential threats for any ETC would be from other civilizations and planets hosting such civilizations would also be copious sources of information, these objectives would lead it to gather information from these locations and to protect itself against them. This dual-goals hypothesis resolves the Fermi paradox, redirects the search for extraterrestrial intelligence and makes testable predictions regarding ETC’s behavior on Earth if it is here. (shrink)

If the discovery of life elsewhere in the universe is just around the corner, what would be the consequences for religion? Would it represent another major conflict between science and religion, even leading to the death of faith? Some would suggest that the discovery of any suggestion of extraterrestrial life would have a greater impact than even the Copernican and Darwinian revolutions. It is now over 50 years since the first modern scientific papers were published on the search for extraterrestrial (...) intelligence. Yet the religious implications of this search and possible discovery have never been systematically addressed in the scientific or theological arena. SETI is now entering its most important era of scientific development. New observation techniques are leading to the discovery of extra-solar planets daily, and the Kepler mission has already collected over 1000 planetary candidates. This deluge of data is transforming the scientific and popular view of the existence of extraterrestrial intelligence. Earth-like planets outside of our solar system can now be identified and searched for signs of life. Now is a crucial time to assess the scientific and theological questions behind this search. This book sets out the scientific arguments undergirding SETI, with particular attention to the uncertainties in arguments and the strength of the data already assembled. It assesses not only the discovery of planets but other areas such as the Fermi paradox, the origin and evolution of intelligent life, and current SETI strategies. In all of this it reflects on how these questions are shaped by history and pop culture and their relationship with religion, especially Christian theology. It is argued that theologians need to take seriously SETI and to examine some central doctrines such as creation, incarnation, revelation, and salvation in the light of the possibility of extraterrestrial life. (shrink)

In this paper we continue our study, begun in [5], of the connection between ultraproducts and saturated structures. IfDis an ultrafilter over a setI, andis a structure, the ultrapower ofmoduloDis denoted byD-prod. The ultrapower is important because it is a method of constructing structures which are elementarily equivalent to a given structure. Our ultimate aim is to find out what kinds of structure are ultrapowers of. We made a beginning in [5] by proving that, assuming the generalized continuum hypothesis, (...) for each cardinalαthere is an ultrafilterDover a set of powerαsuch that for all structures,D-prodisα+-saturated. (shrink)

Science has been dazzlingly successful in explaining nature. Scientific advances also have led to certain undesirable, though unintended, side effects, one of which is alienation from the spiritual. Revelation comes from the Divine. But what is the status of authenticity of a particular piece claimed to be revelation? What is its historical validity and current state of preservation? This essay proposes to develop a list of rational criteria, in consultation with all stakeholders, for addressing the subject. The aim is to (...) bring objectivity into this discourse by placing it more on the turf of reason rather than basing it on considerations of faith and prior allegiance. (shrink)

The scientific search for extraterrestrial intelligent life is probably one of the most ambitious projects ever taken in biology. The article discusses methodological problems associated with the search. It is emphasized that investigators of extraterrestrial intelligence, in contrast to investigators of terrestrial matters, have no valid pre-understanding of their subject matter. In this barren setting, utilization of semiotic knowledge is shown to be a prerequisite for achievement of valid data. Owing to methodological shortcomings, it is concluded that the NASA funded (...) project SETI (Search for Extraterrestrial Intelligence) has little if any relevance for the detection of intelligent life in other worlds. (shrink)

The possibility of extraterrestrial intelligence (ETI) exists despite no observed evidence, and the risks and benefits of actively searching for ETI (Active SETI) have been debated. Active SETI has been criticized for potentially exposing humanity to existential risk, and a recent game-theoretical model highlights the Hobbesian trap that could occur following contact if mutual distrust leads to mutual destruction. We argue that observing a nearby ETI would suggest the existence of many unobserved ETI. This would expand the game (...) and implies that there may be a mechanism that prevents ETI from attacking us. As a result, the Hobbesian trap would be avoided if both parties assumed the other is not likely to attack. (shrink)

James Wynn’s timely investigation highlights scientific studies grounded in publicly gathered data and probes the rhetoric these studies employ. Many of these endeavors, such as the widely used SETI@home project, simply draw on the processing power of participants’ home computers; others, like the protein-folding game FoldIt, ask users to take a more active role in solving scientific problems. In Citizen Science in the Digital Age: Rhetoric, Science, and Public Engagement, Wynn analyzes the discourse that enables these scientific ventures, as (...) well as the difficulties that arise in communication between scientists and lay people and the potential for misuse of publicly gathered data. (shrink)

In [6], Metakides and Nerode introduced the study of the lattice of recursively enumerable substructures of a recursively presented model as a means to understand the recursive content of certain algebraic constructions. For example, the lattice of recursively enumerable subspaces,, of a recursively presented vector spaceV∞has been studied by Kalantari, Metakides and Nerode, Retzlaff, Remmel and Shore. Similar studies have been done by Remmel [12], [13] for Boolean algebras and by Metakides and Nerode [9] for algebraically closed fields. In all (...) of these models, the algebraic closure of a set is nontrivial., is given in §1, however in vector spaces, cl is just the subspace generated byS, in Boolean algebras, cl is just the subalgebra generated byS, and in algebraically closed fields, cl is just the algebraically closed subfield generated byS.)In this paper, we give a general model theoretic setting in which we are able to give constructions which generalize many of the constructions of classical recursion theory. One of the main features of the modelswhich we study is that the algebraic closure of setis just itself, i.e., cl = S. Examples of such models include the natural numbers under equality 〈N, = 〉, the rational numbers under the usual ordering 〈Q, ≤〉, and a large class ofn-dimensional partial orderings. (shrink)

Intermediate prepositional logics we consider here describe the setI() of regular informational types introduced by Yu. T. Medvedev [7]. He showed thatI() is a Heyting algebra. This algebra gives rise to the logic of infinite problems from [13] denoted here asLM 1. Some other definitions of negation inI() lead to logicsLM n (n ). We study inclusions between these and other systems, proveLM n to be non-finitely axiomatizable (n ) and recursively axiomatizable (n ). We also show that formulas (...) in one variable do not separateLM from Heyting's logicH, andLM n (n ) from Scott's logic (H+S). (shrink)

A result of Soare and Stob asserts that for any non-recursive r.e. setC, there exists a r.e.[C] setA such thatA⊕C is not of r.e. degree. A setY is called [of]m-REA (m-REA[C] [degree] iff it is [Turing equivalent to] the result of applyingm-many iterated ‘hops’ to the empty set (toC), where a hop is any function of the formX→X ⊕W e X . The cited result is the special casem=0,n=1 of our Theorem. Form=0,1, and any (m+1)-REA setC, ifC is not ofm-REA (...) degree, then for alln there exists an-r.e.[C] setA such thatA ⊕C is not of (m+n)-REA degree. We conjecture that this holds also form≥2. (shrink)

Stephen Jay Gould's Wonderful Life is a study of the fossils of the Burgess Shale of British Columbia. My concern is with the morals that Gould draws, with the ?new picture of life? that, he says, the reinterpreted Burgess animals compel. I conclude that his case is not established. (1) There may have been reasons to do with ?fitness? why most of the Burgess animals left no descendants, even if we cannot guess exactly what they were. (2) We do not (...) know that our past is dotted with the kind of mass extinctions that are needed for the random evolution that he proposes. (3) Even if what happened does rest on random variation and largely random selection, it does not follow that there are no standing forms that will be constantly re?instantiated. If Rational Life, in particular, is not special, then we have no right to think the world we experience bears any remote resemblance to a putative real world. (4) Even if there are no such forms, the fact that nothing in the state of things required us to exist is no good reason to say that No one requires us to. What Gould says does count against a simple progressivism, but not against an older and more orthodox theology. It also has implications for the Search for Extra?Terrestrial Intelligence (SETI). (shrink)

Intelligent design is the science that studies how to detect intelligence. Recall astronomer Carl Sagan’s novel Contact about the search for extraterrestrial intelligence (or SETI). Sagan based the SETI researchers’ methods of design detection on scientific practice. Real-life SETI researchers have thus far failed to detect designed signals from distant space. But if they encountered such a signal, as the astronomers in Sagan’s novel did, they too would infer design. Intelligent design research currently focuses on developing reliable (...) methods of design detection and then applying these methods, especially to biological systems. (shrink)

The search for extra-terrestrial intelligence (SETI) raises a number of scientific/philosophical questions. If we are the only conscious, intelligent species in the galaxy, why? If we are not, given that other cultures must be more technically advanced than us, why haven't we met them yet?

It is a theorem of Prikry [7] that ifκcarries a uniformη-descendingly complete ultrafilter then the stationary reflection propertyfails. In this paper we will derive similar results, but here from properties of filters rather than ultrafilters.Throughoutκandηwill denote regular cardinals withη<κ, andIwill denote an ideal onκ, by which we mean a setI⊆P such that Iis closed under taking subsets and finite unions and αЄIfor eachα<κ, butκ∉I.Iis said to beμ-complete if it is closed under taking unions of size <μ,I* = {X⊆κ∣κ−XЄI} is (...) the filter dual toIand ifAЄI+ −I), thenI∣Ais the ideal onκgiven byI∣A= {X⊆κ∣X∩AЄI}. Ifh: A→κthenhis said to be unbounded modIif for eachα<κ,h−1 = {ξЄA∣h<α} ЄIand a least function forIifhis unbounded modIand wheneverg: A→κis a function, unbounded modI, then {ξЄA∣g{ξ) shrink)

LetXbe a standard Borel space, and letEbe acountableBorel equivalence relation onX, i.e., a Borel equivalence relationEfor which every equivalence class [x]Eis countable. By a result of Feldman-Moore [FM],Eis induced by the orbits of a Borel action of a countable groupGonX.The structure of general countable Borel equivalence relations is very little understood. However, a lot is known for the particularly important subclass consisting of hyperfinite relations. A countable Borel equivalence relation is calledhyperfiniteif it is induced by a Borel ℤ-action, i.e., by (...) the orbits of a single Borel automorphism. Such relations are studied and classified in [DJK]. It is shown in Ornstein-Weiss [OW] and Connes-Feldman-Weiss [CFW] that for every Borel equivalence relationEinduced by a Borel action of a countable amenable groupGonXand for every probability measure μ onX, there is a Borel invariant setY⊆Xwith μ = 1 such thatE↾Y is hyperfinite. Motivated by this result, Weiss [W2] raised the question of whether everyEinduced by a Borel action of a countable amenable group is hyperfinite. Later on Weiss showed that this is true forG= ℤn. However, the problem is still open even for abelianG. Our main purpose here is to provide a weaker affirmative answer for general amenableG. We need a definition first. Given two standard Borel spacesX, Y, auniversally measurableisomorphism betweenXandYis a bijection ƒ:X→Ysuch that both ƒ, ƒ-1are universally measurable. Notice now that to assert that a countable Borel equivalence relation onXis hyperfinite is trivially equivalent to saying that there is a standard Borel spaceYand a hyperfinite Borel equivalence relationFonY, which isBorelisomorphic toE, i.e., there is a Borel bijection ƒ:X→YwithxEy⇔ ƒFƒ. We have the following theorem. (shrink)

Paneb foi um trabalhador da aldeia de Deir el-Medina que viria a ocupar uma posição de relativo destaque a partir do ano 5 de Seti II como «chefe da equipa do lado esquerdo do grupo» e que está associado a um caso judicial em que é acusado por Amennakht, seu tio adoptivo, de uma série de subornos, roubos, abusos de autoridade, ataques físicos, violações, adultério e até assassinato, cometidos na sua aldeia e no Vale dos Reis ao longo de (...) um quarto de século no final da XIX dinastia. Os crimes de que é acusado são conhecidos em detalhe através do Papiro Salt 124 (BM 10055), datado da XX dinastia (provavelmente do ano 6 de Ramsés III). Esta fonte é um documento extraordinário para se compreender o funcionamento da Administração e da Justiça no Império Novo, mas a sua análise permite detectar exageros e deformações dos factos que nos obrigam a reavaliar o seu verdadeiro significado. (shrink)

This essay argues for a more methodologically diverse search for extraterrestrial intelligence (SETI) and study of habitable exoplanets that might contribute to the emergent field of critical habitability studies across the sciences and humanities. Whether or not contact is made with extraterrestrials, this effort is implicated in changing concepts of otherness at home and the ongoing work to decolonize Earth and make it more inhabitable. I examine historical efforts to think aliens philosophically in the work of Kant, to conclude (...) with a reflection on the trope of contact between humans, nonhuman animals, and aliens in Ted Chiang’s short story “The Great Silence.”. (shrink)

Extraterrestrial Altruism examines a basic assumption of the Search for Extraterrestrial Intelligence (SETI): that extraterrestrials will be transmitting messages to us for our benefit. This question of whether extraterrestrials will be altruistic has become increasingly important in recent years as SETI scientists have begun contemplating transmissions from Earth to make contact. Technological civilizations that transmit signals for the benefit of others, but with no immediate gain for themselves, certainly seem to be altruistic. But does this make biological sense? (...) Should we expect altruism to evolve throughout the cosmos, or is this only wishful thinking? Is it dangerous to send messages to other worlds, as Stephen Hawking has suggested, or might humankind benefit from an exchange with intelligence elsewhere in the galaxy? Would extraterrestrial societies be based on different ethical principles, or would we see commonalities with Earthly notions of morality? Extraterrestrial Altruism explores these and related questions about the motivations of civilizations beyond Earth, providing new insights that are critical for SETI. Chapters are authored by leading scholars from diverse disciplines—anthropology, astronomy, biology, chemistry, computer science, cosmology, engineering, history of science, law, philosophy, psychology, public policy, and sociology. The book is carefully edited by Douglas Vakoch, Director of Interstellar Message Composition at the SETI Institute and professor of clinical psychology at the California Institute of Integral Studies. The Foreword is by Frank Drake. This interdisciplinary book will benefit everybody trying to understand whether evolution and ethics are unique to Earth, or whether they are built into the fabric of the universe. (shrink)

Communication with other life forms in our universe has been an ongoing effort most notably conducted by the Search for Extraterrestrial Intelligence Project (SETI). Whereas SETI uses a network of radio telescopes to search for frequencies that may indicate intelligent design, there are also attempts to communicate with extraterrestrials by using different ways to listen for messages as well as send messages. This article outlines a phenomenological approach that includes changes in cognition due to the creation of electronic (...) sounds mixed with stellar acoustics, radio frequencies, and natural and manmade sounds as a way of experiencing changes in cognitive states. These cognitive states may be related to a conscious contact with other life forms not from our world. In this sense it is a galactic approach to interspecies communication. (shrink)

Anthropic reasoning has lately been strongly associated with the string theory landscape and some theories of particle cosmology, such as cosmological inflation. The association is not, contrary to multiple statements by physicists and philosophers alike, necessary. On the contrary, there are clear reasons and instances in which the anthropic reasoning is useful in a diverse range of fields such as planetary sciences, geophysics, future studies, risk analysis, origin of life studies, evolutionary theory, astrobiology and SETI studies, ecology, or even (...) strategic studies and global policy. The association of anthropic reasoning with string theory and particle cosmology has not only become the standard wisdom, but has been often construed in a negative way, in order to demonstrate or insinuate that such reasoning is too abstract or even belongs to 'fringe science', remote from run-of-the-mill research practices in any other more 'mundane' and less theoretical scientific discipline. The purpose of this paper is to (i) analyse some of the counter-examples to the standard wisdom, (ii) suggest that the anthropic reasoning is more flexible, more general, and less fashion-driven than the detractors state. In addition, we consider some historical and/or extrascientific motivation for this persistent prejudice. (shrink)

An interesting consequence of the modern cosmological paradigm is the spatial infinity of the universe. When coupled with naturalistic understanding of the origin of life and intelligence, which follows the basic tenets of astrobiology, and with some fairly incontroversial assumptions in the theory of observation selection effects, this infinity leads, as Ken Olum has recently shown, to a paradoxical conclusion. Olum's paradox is related, to the famous Fermi's paradox in astrobiology and “SETI” studies. We, hereby, present an evolutionary argument (...) countering the apparent inconsistency, and show how, in the framework of a simplified model, deeper picture of the coupling between histories of intelligent/technological civilizations and astrophysical evolution of the Galaxy, can be achieved. This strategy has consequences of importance for both astrobiological studies and philosophy. (shrink)

We consider the Search for ExtraTerrestrial Intelligence (SETI) activities from a bioethical standpoint. In particular, we argue that there is a moral duty to search for other intelligent beings in the Universe. Some of them could – and are likely to be – morally enhanced in the sense that they are not only capable of unmistakable moral reasoning but are also capable of consistently acting upon the results of such deliberations. Even if the probability of finding such morally superior (...) beings is small, it is higher than zero in any case; in fact, our astrobiological knowledge suggests that this probability is significant. Hence, there are both deductive and inductive arguments for the proposition that our duty is to search for such morally superior extraterrestrial beings. In other words, there is a duty to undertake and support our SETI efforts. The argument to that effect runs parallel to some of the arguments deployed in current debates on human moral enhancement. (shrink)

Anthropic reasoning has lately been strongly associated with the string theory landscape and some theories of particle cosmology, such as cosmological inflation. The association is not, contrary to multiple statements by physicists and philosophers alike, necessary. On the contrary, there are clear reasons and instances in which the anthropic reasoning is useful in a diverse range of fields such as planetary sciences, geophysics, future studies, risk analysis, origin of life studies, evolutionary theory, astrobiology and SETI studies, ecology, or even (...) strategic studies and global policy. The association of anthropic reasoning with string theory and particle cosmology has not only become the standard wisdom, but has been often construed in a negative way, in order to demonstrate or insinuate that such reasoning is too abstract or even belongs to “fringe science”, remote from run-of-the-mill research practices in any other more “mundane” and less theoretical scientific discipline. The purpose of this paper is to analyse some of the counter-examples to the standard wisdom, suggest that the anthropic reasoning is more flexible, more general, and less fashion-driven than the detractors state. In addition, we consider some historical and/or extrascientific motivation for this persistent prejudice. (shrink)

Both “optimists” and “sceptics” in regard to extraterrestrial intelligence tend to hold the view that we are entitled to an epistemically clear position: either there will be a signal, in the sufficiently general sense, proving the existence of extraterrestrial intelligence, or no such signal is forthcoming. The distinction, I wish to argue here, is not at all so clear-cut. On the contrary, there are arguments, intrinsic to the subject matter, to the effect that the detection of ETI will be a (...) protracted affair characterized by uncertainty at every step. Such view of SETI discovery mandates different policies from those conventionally discussed in the literature. We should not gear our expectations and publicly promote the view that the Contact will be a clear-cut, Archimedean “Eureka!”-style discovery. In contrast, the tempo and mode of the process of discovery might significantly influence societal and political reactions to the discovery. We should be prepared for such a protracted unfolding of events. (shrink)

It has already become a commonplace to discuss postbiological evolution in various contexts of futures studies, bioethics, cognitive sciences, philosophical anthropology, or even economics and SETI studies. The assumption is that technological/cultural evolution will soon entirely substitute for the biological processes which underlie human existence – and, by analogy, the existence of other independently evolved intelligent beings, if any. Various modes of postbiological evolution of humans have been envisioned in both fictional and discursive contexts. Little thought has been devoted (...) so far to the question whether these postbiological modes are truly final in both logical and conceptual terms. What lies beyond the postbiological realm? Clearly, only a few radical speculations on the topic can be offered. In this paper, it is argued that in a sufficiently broad subset of scenarios for postbiological evolution there will be a kind of reverse trend: the one of reintegration with the biological universe, by that point understood in a much wider and more inclusive sense. The argument for such reintegration could be understood through the metaphor of expanding Klein bottle as a symbolic image of the post-postbiological evolutionary trajectories. This kind of trajectory will lead to the state in which products of culture are indistinguishable from the natural environment, suggesting practical consequences for our SETI efforts. (shrink)

Stephen Hawking’s caution against messaging extraterrestrial intelligence is a claim of universal biology and is probably false.

Cosmology seems extremely remote from everyday human practice and experience. It is usually taken for granted that cosmological data cannot rationally influence our beliefs about the fate of humanity—and possible other intelligent species—except perhaps in the extremely distant future, when the issue of “heat death” (in an ever-expanding universe) becomes actual. Here, an attempt is made to show that it may become a practical question much sooner, if an intelligent community wishes to maximize its creative potential. We estimate, on the (...) basis of a greatly simplified model, the rate of loss of potentially useful information due to the delay in undertaking the colonization of the largest gravitationally bound structures in an accelerating universe. In addition, we argue for a natural cosmological extension of the classical taxonomy of advanced technological communities given by Kardashev. New developments in the fields of anthropic self-selection and physical eschatology give, for the first time, solid foundations to such results. This may open some new (and possibly urgent) issues in the areas of future policy making and transhumanist studies generally. It may also give us a slightly better perspective on the SETI endeavor. (shrink)

We consider how a rational decision theorist would justify committing resources to an investigation designed to satisfy pure curiosity. We derive a strange result about the need to be completely open-minded about the outcome.